1. Field of the Invention
The invention relates to a method for operating a hearing aid, as well as to a hearing aid system with at least two microphones and a signal processing unit.
2. Description of the Prior Art
Wind frequently causes unpleasant disturbing noises for the wearer of a hearing aid. In order to reduce such wind noise, it is known to fit the microphone openings so as to protect them from the wind as much as possible. It is also known to provide hearing aid microphones with a diaphragm in order to reduce instances of turbulence caused by wind. Such measures are disclosed, for example, in PCT Application WO 00/02419 and German PS 44 26 967.
German PS 44 98 516 discloses a directional gradient microphone system and a method for operating it employing three microphones and a processor. Owing to the arrangement of the three microphones on a common axis, it is only sound waves incident in the direction of the common axis which are processed after being converted into electric signals, whereas sound waves caused by wind noises, for example, after being converted into electric signals, virtually no longer occur in the output signal of the directional gradient microphone system. This known directional gradient microphone system has the disadvantage, however, that it is possible to suppress wind noises only in conjunction with a strong directional dependence in the reception of incoming sound waves.
It is a disadvantage in known hearing aids that success in removing wind noises is therefore frequently inadequate.